1. Field of the Invention
The present invention relates to a toothbrush, and more particularly to a toothbrush for controlling back-and-forth reciprocating distance of toothbrushing, i.e., brushing stroke, at the time when one brushes one's teeth.
2. Description of the Related Art
In recent years, it has come to be understood that plaque and food particles cannot be completely removed from the teeth by the so-called "rolling method" wherein the toothbrush is rotated in terms of toothbrushing methods. At present, it is understood that the brushing with short back-and-forth strokes called as "Bass' method" or "scrubbing method" in which the toothbrush is moved back and forth with a distance of several millimeters (hereinafter referred to as the short stroke brushing) is most appropriate in terms of plaque control.
However, the actual situation is such that most people perform the "horizontal method" or the brushing with long back-and-forth strokes with a long distance of about 15-50 mm (hereinafter referred to as the long stroke brushing). Although the long stroke brushing gives an impression that it is apparently effectual and brushes well, the bristles come into contact with only the projecting surfaces of teeth and do not reach those boundary areas between the teeth and the gums, recessed portions between the teeth or fine grooves on the clenching surfaces of the teeth that require brushing. Accordingly, there are problems that, over a long period of years, the so-called wedge-shaped loss results in which projecting surfaces of the teeth and the gums become worn, and that periodontosis and decayed teeth also result due to the incomplete cleaning at the aforementioned boundary areas and the like.
Accordingly, it is necessary to carry out the above-described short stroke brushing. Nevertheless, it is extremely difficult for ordinary people to master the procedure of the short stroke brushing. The actual situation is such that, if one who has mastered it neglects to exercise caution, the brushing strokes become large before he is aware of it, resulting in the long stroke brushing.
Conventionally, there has been proposed a toothbrush device designed to correct a method of brushing teeth, as disclosed in Japanese Utility Model Publication No. 16664/1983 . (which corresponds to Fujita U.S. Pat. No. 4,253,212). However, this device has been proposed strictly for the purpose of leading a person to brush his teeth with a low back-and-forth speed of the toothbrush, and it is not designed to effect the short stroke brushing described above. With this conventional toothbrush device, however, it may be impossible for one to master the appropriate short stroke brushing.